Wideband Sparse Signal Acquisition Based on Serial Multi-Coset Sampling

Changjian Liu,Houjun Wang

doi:10.1155/2018/9208568

Abstract

Traditional parallel multi-coset sampling (MCS), which has several sub-Analog-to-Digital-Converters (sub-ADCs) working parallelly, is an attractive sub-Nyquist sampling technique for wideband sparse signals. However, the mismatch among sub-ADCs in traditional parallel MCS, such as bias, gain, and timing skew mismatch, degrades the signal acquisition performance greatly. In this paper, a serial MCS scheme based on clocking single ADC with nonuniform clock is proposed. The nonuniform sampling clock is generated by a pseudo-random binary sequence generator. An additional Sample/Hold (S/H) is used to improve the analog bandwidth of the serial MCS. Moreover, universal sampling pattern is designed for the proposed serial MCS. The sampling pattern design should not only maximize the Kruskal rank of compressed sensing matrix but also take the ADC’s sub-Nyquist sampling rate into consideration. Numeral experiments are presented demonstrating that the mismatch among sub-ADCs in traditional parallel MCS degrades the reconstruction performance greatly, and the proposed serial MCS can avoid the mismatch tactfully.

Highlights

Wideband sparse signal is called a multiband signal
The reconstruction results of the proposed serial multi-coset sampling (MCS) and traditional parallel MCS are shown in Figures 6 and 7, respectively
A serial MCS is proposed based on clocking single Analog to Digital Converter (ADC) with nonuniform clock for acquiring wideband sparse signal

Summary

Introduction

Wideband sparse signal is called a multiband signal. Its frequency support concentrates on several continuous intervals and is distributed over a wide spectrum [1]. Several sub-Nyquist sampling techniques have been proposed to acquire multiband signal at a sub-Nyquist rate [1,2,3,4,5,6,7,8,9]. Let M denote the number of subbands within X(f) and it is even because of the conjugate symmetry property of a real signal’s Fourier transform. It can be implemented on a timeinterleaved ADC platform by only implementing p out of L sub-ADCs. So the overall system sampling rate is (p/L) × fN. The mismatch among sub-ADCs, such as bias, gain, and timing skew mismatch, will deteriorate the signal reconstruction performance of TIADC, so does the multi-coset sampling system. Many methods have been proposed to compensate the mismatch [10, 11], this will bring about a large amount of work on calibration

Serial Multi-Coset Sampling

Universal Sampling Pattern Design

Results and Discussion

Conclusion